This section provides background information related to the present disclosure which is not necessarily prior art.
As a result of environmental and other concerns, plastic containers, more specifically polyester and even more specifically polyethylene terephthalate (PET) containers are now being used more than ever to package numerous commodities previously supplied in glass containers. Manufacturers and fillers, as well as consumers, have recognized that PET containers are lightweight, inexpensive, recyclable and manufacturable in large quantities.
Container manufacturers use mechanical processing and thermal processing to increase the PET polymer crystallinity of a container. Mechanical processing involves orienting the amorphous material to achieve strain hardening. This processing commonly involves stretching an injection molded PET preform along a longitudinal axis and expanding the PET preform along a transverse or radial axis to form a PET container. The combination promotes what manufacturers define as biaxial orientation of the molecular structure in the container.
Traditionally blow molding and filling have developed as two independent processes, in many cases operated by different companies. In order to make bottle filling more cost effective, some fillers have moved blow molding in house, in many cases integrating blow molders directly into their filling lines. The equipment manufacturers have recognized this advantage and are selling “integrated” systems that are designed to insure that the blow molder and the filler are fully synchronized. Despite the efforts in bringing the two processes closer together, blow molding and filling continue to be two independent, distinct processes. As a result, significant costs may be incurred while performing these two processes separately. Thus, there is a need for a liquid or hydraulic blow molding system suitable for forming and filling a container in a single operation. Moreover, there is a need for a modified preform that is particularly well-suited for molding system that form and fill a container in a single operation.